Out of the following coordination entities,which is chiral (optically active)?

Change in composition of the coordination sphere yields which type of isomers?

The number of possible optical isomers for $[Co(en)_2 Cl_2]^+$ is ....

$26.7 \ g$ of a compound with the formula $PtCl_2Br_2 \cdot 6H_2O$ is taken for analysis. This compound exhibits stereoisomerism,and a total of $3$ stereoisomers exist. Find the loss in mass (in $g$) when the given amount of the compound is treated with concentrated $H_2SO_4$. (Molar mass: $PtCl_2Br_2 \cdot 6H_2O = 534 \ g \ mol^{-1}$)

Arrange the following in the increasing order of the number of unpaired electrons present in the central metal ion:
$I.$ $[MnCl_6]^{3-}$
$II.$ $[FeF_6]^{3-}$
$III.$ $[Mn(CN)_6]^{3-}$
$IV.$ $[Fe(CN)_6]^{3-}$

The magnetic moment of the complex $[Cr(CN)_6]^{3-}$ is ..... (in $BM$)